In this study, we focused on the adhesion and friction behaviors of probes approaching magnetic disk surfaces. In order to observe these behaviors, a micro-tribotester was newly developed to evaluate the friction and adhesion forces of the ultrathin lubricant film on magnetic disks. The contact area between the spherical glass surface and the disk surface was measured using light intensities and Newton's rings and approximated by the JKR model. An adhesion force corresponding to a pull-off force acted on the interface between the glass surface and the disk surface. The friction coefficients on disks with different lubricant thicknesses were measured and the coefficient was found to decrease as the lubricant thickness increased. The pull-off force gradually increased as lubricant thickness increased.